Go to definition (documentation) for built-in classes

In VSCode I can use the "Go to definition" feature on any built-in class and it'll open up a .gddoc file with the documentation for it.

Super useful to see the list of all methods, signals etc without having to go Godot's documentation website each time.

Using the "Go to definition" feature in Zed it'll simply open up the list of references. I'm guessing it's a fallback as the Definition is not defined 🤷. I'm not sure where VSCode is pulling the .gddoc file from but it would be great if we could have a similar feature in Zed to access the documentation without having to leave the editor.

No files or entry points are named. First reproduce Go to definition on a built-in Godot class in Zed, then trace the extension's handling of the current references fallback and compare it with VSCode's .gddoc behavior. Done means the command opens the class documentation instead of only the references list.

Written by the indexing model from the issue text.